Under physiological conditions, the nose functions to provide active warming and humidifying of breathing air. However, when a patient is undergoing artificial respiration the nose is shunted by a flexible tube, whose distal end is inserted into the trachea. In order to prevent unwanted effects such as cough stimulus or draining of the mucous membranes, the breathing air supplied must be treated. This is necessary, because the nose and throat mucous membranes, which normally take over this task, are no longer available under these circumstances. The moistening and warming treatment of the supplied breathing gases, which is essential for normal function of the lungs and nose, is nowadays performed by devices usually composed of an optional filtering apparatus and of a humidifying and heating apparatus, herein also referred as artificial noses.
Artificial noses are known in the art such as in EP 0 413 127, which described an apparatus for warming and moistening breathing air for artificial respiration wherein heating and humidifying are obtained by a combination of independent passive heat and moisture exchangers with an active heat and moisture exchanger. However, this device is relatively complex in design. WO 97/07845 discloses an apparatus for compensating heat and humidity loss in a device that administers or restitutes warm and humid air to a patient.
It is a main object of the present invention to provide a device for the conditioning of breathing air, which can maintain the heat level and the humidity proportion of said breathing air at the requested level. It is another object of the present invention to provide a device for the conditioning of breathing air wherein said air can be further filtered. It is a further object to provide a device for the conditioning of breathing air which is an all-in-one device having passive humidifying and active humidifying functions, which can be connected to an air supply duct at an arbitrary localization so that a very great flexibility of the device is assured. It is yet another object to provide a device for the conditioning of breathing air capable of preventing water condensation in said air supply duct so that the provision of water traps provided in all existing apparatuses until now are no longer needed.